In the field of conveyors, it is known to mount trucks on a solid, impervious flooring under which is provided a magnetic conveyor which causes the trucks to move above the flooring by reason of cooperating magnets mounted under the trucks. Examples are shown, e.g., in U.S. Pat. Nos. 2,609,915 and 2,824,638. However, such trucks have limited capability such as is not particularly useful in a clinical analyzer. That is, they provide fixed horizontal surfaces that lack receptacles needed for sample tubes or pipette tips that have to be carried in an analyzer. Furthermore, they are not capable of rotation on the trucks as is necessary to present multiple positions to a single station. More specifically, they are not freely rotatable on the magnetic base that responds to the magnetic drive underneath.
Therefore, there has been a need for magnetic conveyors that can provide a drive to move a sample tube tray from a loading station to a sample aspiration station, the tray being constructed with receptacles suitable for at least a plurality of sample tubes, and so as to be freely rotatable.
In the field of trays for sample tubes, it is known to provide movable second tube supports that are insertable into the tray above the fixed supports to allow shorter tubes and tubes of varying diameters to be supported by the inserted supports. Examples of such trays are shown, for example, in EPA 467,301 (Doc. 60240). Although such trays function very well, there is a disadvantage: the inserted second supports, when removed from their inserted position, are no longer attached to the tray. As a result, it is possible for the second supports to be lost or misplaced once removed, so that when another second support is required for a particular tray, there is no longer one available. Yet, it is difficult to connect the insertable second supports to the tray without them getting in the way when they are not in use.
Therefore, prior to this invention, there has been a need for a tray that provides a movable second support for tubes above the fixed support, that is permanently connected to the tray without interference, when not in use.